Previous Article | Next Article ![]()
Antimicrobial Agents and Chemotherapy, 07 1995, 1419-1424, Vol 39, No. 7
JM Entenza, H Drugeon, MP Glauser and P Moreillon
RP 59500 is a new injectable streptogramin composed of two synergistic
components (quinupristin and dalfopristin) which are active against
erythromycin-susceptible and -resistant gram-positive pathogens. The
present experiments compared the therapeutic efficacy of RP 59500 with that
of vancomycin against experimental endocarditis due to either of two
erythromycin-susceptible or two constitutively erythromycin- resistant
isolates of methicillin-resistant Staphylococcus aureus. RP 59500 had low
MICs for the four test organisms as well as for 24 additional isolates (the
MIC at which 90% of the isolates were inhibited was < 1 mg/liter) which
were mostly inducibly (47%) or constitutively (39%) erythromycin resistant.
Aortic endocarditis in rats was produced with catheter-induced vegetations.
Three-day therapy was initiated 12 h after infection, and the drugs were
delivered via a computerized pump, which permitted the mimicking of the
drug kinetics produced in human serum by twice-daily intravenous injections
of 7 mg of RP 59500 per kg of body weight or 1 g of vancomycin. Both
antibiotics reduced vegetation bacterial titers to below detection levels
in ca. 70% of animals infected with the erythromycin-susceptible isolates
(P < 0.05 compared with titers in controls). Vancomycin was also
effective against the constitutively resistant strains, but RP 59500 failed
against these isolates. Further experiments proved that RP 59500 failures
were related to the very short life span of dalfopristin in serum (< or
= 2 h, compared with > or = 6 h for quinupristin), since successful
treatment was restored by artificially prolonging the dalfopristin levels
for 6 h.(ABSTRACT TRUNCATED AT 250 WORDS)
Copyright © 1995 by the American Society for Microbiology. All rights reserved.
Treatment of experimental endocarditis due to erythromycin-susceptible or -resistant methicillin-resistant Staphylococcus aureus with RP 59500
Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»